New research linking the level of certain nutrients in the body to mental illness could reduce the risk of those who are vulnerable, and improve the outcomes of people already diagnosed with conditions.

The study, led by researchers from the NICM Health Research Institute at Western Sydney University, found that deficiencies, particularly in folate (vitamin B) and vitamin D, were “significantly” more likely among those experiencing early psychosis.

“There’s more evidence arising that nutrition and particularly poor nutrition may be impacting on people’s mental health and conditions like depression and low mood,” said lead author, postdoctoral research fellow Joseph Firth.

For the first time, through a metaanalysis of 2612 individuals, they found that many of those experiencing psychotic episodes (which may be a one-off instance or may develop into schizophrenia, which is the longer-term condition) are dangerously deficient.

“Right away, as soon as they are presenting with psychotic symptoms, they have low folate – which is really important for brain health – and low vitamin D, which is also a neuroprotective nutrient; both key factors in people’s mood and energy levels,” Dr Firth explained.

“The patients with the lower levels of these nutrients also had the worst mental health. Even if you’ve got psychosis, people with high levels of these nutrients had better mental health.”

For any of us – mentally ill or not – a poor diet, low in certain blood nutrients will leave us “feeling pretty crappy”, Dr Firth says.

But this is exacerbated for people at risk of or experiencing a mental illness.

“It appears there’s great scope for improving nutrition and improving nutritional profiles not to cure schizophrenia but to massively improve the physical and mental health outcomes of young people with this type of condition,” Dr Firth said.

This is because pharmaceuticals used to treat psychosis, for example, may be effective at tackling part of the problem (like paranoia or voices), but not the whole nor the side-effects.

Many people with schizophrenia also experience poor cognitive function including poor memory and concentration as well a tendency to socially withdraw.

“These negative symptoms grind people down and really impede people’s ability to have a fulfilling life, even after their psychotic symptoms have been treated,” Dr Firth said.

“The antipsychotics do nothing for these other aspects of the illness, in fact, people think in some cases they make them worse, so we need new treatments and new approaches to help the social withdrawal and low motivation symptoms as well as the cognitive functioning symptoms – and nutrition is emerging as one of the most promising ways to do that, along with things like exercise.”

In terms of whether a poor diet could make us more susceptible to mental illness, there are no blanket rules and causes vary greatly.

That said, there are rare cases of “very, very low vitamin B12 resulting in psychotic episodes”, said Dr Firth, who suggests addressing diet first (foods rich in folate include leafy greens, avocados, orange juice, legumes and liver; vitamin B12 foods include eggs, dairy and meat; while vitamin D foods include fatty fish, such as mackerel, tuna and salmon) before looking to supplementation.

“There are cases of these conditions clearing up immediately – and this is one in 1000 patients – as soon as they receive their B12 injection,” he said.

Similarly, Dr Firth said there are rare cases of people with major depression who are very low in B vitamins and show major improvement once the deficiency is remedied.

But for most people, improving diet is an important mental health adjunct and can support better outcomes for those struggling.

“As well as eating the nutritional foods, you’ve got to avoid the nutritionally devoid foods because they rob your body of nutrition and increase your levels of inflammation and oxidative stress – things that have a really nasty effect on your mental health,” Dr Firth said. “That’s important too – concentrating on what you are eating but also concentrating on what you aren’t eating.

“The overall message is that nutrition could have a big impact on the physical health and also the mental health of young people with psychosis and correcting nutrition… could have a positive impact on improving people’s outcomes. For facilitating full recovery, nutrition could be the missing part of the puzzle and, when we fix it, could lead to much healthier lives and much happier, recovery-focused lives.”